TPS54340: How to read a frequency response graph

Takashi Onawa

Part Number: TPS54340

Hi Team,

We can tune system frequency response by Spreadsheet, TPS54360-361FAMILY_CALC_TOOL_REVE though, but I'm not sure which part of the transfer function each GAIN line on the frequency response graph are for.

I can see three line on the graph as below. Could you please explain which part of the transfer function each line represents?

Power Stage Gain :
Compensation Gain :
Overall Gain :

Regards,

Takashi Onawa

over 3 years ago

0 Daniel Li14 over 3 years ago

TI__Mastermind 27040 points

Hi:

power stage gain: transfer function from COMP to VO

compensation gain, tranfer function from Vo to COMP

Overall Gain : open loop gain.

Thank

0 Takashi Onawa over 3 years ago in reply to Daniel Li14

TI__Genius 13200 points

Hi Daniel-san,

Thanks for your prompt response on this.

Let me check to make sure. Is "Overall" an open-loop transfer function rather than a loop transfer function?

I understand the difference between the two as follows.

Open-loop transfer function : Transfer function represented the ratio of input to output(Not including FB factors)
Loop transfer function : Transfer function that circles the entire loop(Including FB factors)

Regards,

Takashi Onawa

0 Daniel Li14 over 3 years ago in reply to Takashi Onawa

TI__Mastermind 27040 points

it is loop transfer function include the FB factors.

Thanks

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TPS54340: How to read a frequency response graph